QHistogram.cpp

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#include "QHistogram.h"
#include "Histogram.h"
#include "IException.h"
#include <QFileDialog>
#include <QPrintDialog>
#include <QPainter>
#include <QPrinter>
#include <QMessageBox>
#include <QFileInfo>
#include <QVBoxLayout>
#include <QLabel>
#include <qwt_plot_curve.h>
#include <qwt_plot_zoomer.h>

using namespace std;
namespace Isis {


  QHistogram::QHistogram(QWidget *parent) : QwtPlot(parent) {
    p_zoomer = new QwtPlotZoomer(this->canvas());
    setTitle("Histogram Plot");

    QwtText *leftLabel = new QwtText("Frequency", QwtText::PlainText);
    leftLabel->setColor(Qt::red);
    QFont font = leftLabel->font();
    font.setPointSize(13);
    font.setBold(true);
    leftLabel->setFont(font);
    setAxisTitle(QwtPlot::yLeft, *leftLabel);

    QwtText *rtLabel = new QwtText("Percentage");
    rtLabel->setColor(Qt::blue);
    rtLabel->setFont(font);
    setAxisTitle(QwtPlot::yRight, *rtLabel);

    setAxisTitle(QwtPlot::xBottom, "Pixel Value (DN)");

    setAxisScale(QwtPlot::yRight, 0, 100);
    enableAxis(QwtPlot::yRight, true);
    setCanvasBackground(Qt::white);
  }


  void QHistogram::Load(Histogram &hist) {
    p_histCurve = new QwtPlotCurve();
    p_histCurve->setStyle(QwtPlotCurve::Lines);

    p_cdfCurve = new QwtPlotCurve();
    p_cdfCurve->setStyle(QwtPlotCurve::Lines);

    //Transfer data from histogram to the plotcurve
    QVector<QPointF> histData;
    QVector<QPointF> cdfData;
    double cumpct = 0.0;
    for(int i = 0; i < hist.Bins(); i++) {
      if(hist.BinCount(i) > 0) {
        histData.append(QPointF(hist.BinMiddle(i), hist.BinCount(i)));

        double pct = (double)hist.BinCount(i) / hist.ValidPixels() * 100.;
        cumpct += pct;
        cdfData.append(QPointF(hist.BinMiddle(i), cumpct));
      }
    }
    QPen *pen = new QPen(Qt::red);
    pen->setWidth(2);
    p_histCurve->setData(new QwtPointSeriesData(histData));
    p_histCurve->setYAxis(QwtPlot::yLeft);
    p_histCurve->setPen(*pen);
    p_histCurve->attach(this);

    pen->setColor(Qt::blue);
    p_cdfCurve->setData(new QwtPointSeriesData(cdfData));
    p_cdfCurve->setYAxis(QwtPlot::yRight);
    p_cdfCurve->setPen(*pen);
    p_cdfCurve->attach(this);

    this->replot();
    p_zoomer->setZoomBase();
  }


  void QHistogram::trackerEnabled() {
    if(p_zoomer->trackerMode() == QwtPicker::ActiveOnly) {
      p_zoomer->setTrackerMode(QwtPicker::AlwaysOn);
    }
    else {
      p_zoomer->setTrackerMode(QwtPicker::ActiveOnly);
    }
  }


  void QHistogram::cdfCurveVisible() {
    p_cdfCurve->setVisible(!p_cdfCurve->isVisible());
    this->replot();
  }


  void QHistogram::printPlot() {
    // Initialize a printer
    static QPrinter *printer = NULL;
    if(printer == NULL) printer = new QPrinter;
    printer->setPageSize(QPrinter::Letter);
    printer->setColorMode(QPrinter::Color);

    QPrintDialog printDialog(printer, (QWidget *)parent());
    if(printDialog.exec() == QDialog::Accepted) {
      // Get display widget as a pixmap and convert to an image
      QPixmap pixmap = this->grab();
      QImage img = pixmap.toImage();

      // C++ Gui Programmign with Qt, page 201
      QPainter painter(printer);
      QRect rect = painter.viewport();
      QSize size = img.size();
      size.scale(rect.size(), Qt::KeepAspectRatio);
      painter.setViewport(rect.x(), rect.y(),
                          size.width(), size.height());
      painter.setWindow(img.rect());
      painter.drawImage(0, 0, img);
    }

  }


  void QHistogram::savePlot() {
    QString output =
      QFileDialog::getSaveFileName((QWidget *)parent(),
                                   "Choose output file",
                                   "./",
                                   QString("Images (*.png *.jpg *.tif)"));
    if(output.isEmpty()) return;

    QString format = QFileInfo(output).suffix();
    QPixmap pixmap = this->grab();
    std::string formatString = format.toStdString();
    if(!pixmap.save(output, formatString.c_str())) {
      QMessageBox::information((QWidget *)parent(), "Error", "Unable to save" + output);
      return;
    }
  }


  void QHistogram::switchBackground() {
    QPen *pen = new QPen(Qt::white);
    if(canvasBackground() == Qt::white) {
      setCanvasBackground(Qt::black);
      p_zoomer->setRubberBandPen(*pen);
      p_zoomer->setTrackerPen(*pen);
    }
    else {
      setCanvasBackground(Qt::white);
      pen->setColor(Qt::black);
      p_zoomer->setRubberBandPen(*pen);
      p_zoomer->setTrackerPen(*pen);
    }
    replot();
  }


  void QHistogram::showHelp() {
    QDialog *d = new QDialog(this);
    d->setWindowTitle("Basic Help");

    QLabel *zoomLabel = new QLabel("Zoom Options:");
    QLabel *zoomIn = new
    QLabel("  <b>Left click</b> on the mouse, drag, and release to select an area to zoom in on");
    QLabel *zoomOut = new
    QLabel("  <b>Middle click</b> on the mouse to zoom out one level");
    QLabel *zoomReset = new
    QLabel("  <b>Right click</b> on the mouse to clear the zoom and return to the original plot");

    QVBoxLayout *layout = new QVBoxLayout();
    layout->addWidget(zoomLabel);
    layout->addWidget(zoomIn);
    layout->addWidget(zoomOut);
    layout->addWidget(zoomReset);

    d->setLayout(layout);
    d->show();
  }

} // end namespace isis